1. Field of the Invention
The present invention relates to an imaging apparatus, and particularly to an imaging apparatus that allows reduction in size of a lens driving portion.
2. Description of the Related Art
FIG. 1 shows the configuration of an exemplary imaging apparatus of related art. An imaging apparatus 10 shown in FIG. 1 includes a housing 11, a lens barrel 12, and an imaging device 13. The imaging apparatus 10 is manufactured by assembling the lens barrel 12 and the imaging device 13 into the housing 11.
Lenses 21, 22, and 23 are assembled into the lens barrel 12 and held therein. A thread 24 is provided on the outer side surface of the lens barrel 12. The thread 24 engages a thread (not shown) provided on a lens carrier 31 disposed in the housing 11. The thread engagement between the lens barrel 12 and the lens carrier 31 allows the distance to the imaging device 13 to be adjusted at the time of manufacture (the focus of the lenses to be adjusted). After the focus adjustment, the lens barrel 12 is glued to the lens carrier 31 so that the lens barrel 12 is fixed to the lens carrier 31.
Coils 32-1 and 32-2 are provided on the side surface of the lens carrier 31. The coils 32-1 and 32-2 are shown as separate members for illustration purposes only, but a single coil 32 is in practice provided on the side surface of the lens carrier 31. A magnet 33-1 is provided in the housing 11 and faces the coil 32-1. Similarly, a magnet 33-2 is provided in the housing 11 and faces the coil 32-2. Each of the magnets 33-1 and 33-2 is provided with a yoke, which is omitted in FIG. 1. The coil 32, the magnets 33, and the yokes form a voice coil motor.
When a current is conducted through the coil 32, a force is produced in the upward or downward direction in FIG. 1. The produced force moves the lens carrier 31 in the upward or downward direction. When the lens carrier 31 is moved, the lens barrel 12 fixed to the lens carrier 31 is also moved. The distance between the lenses 21 to 23 held in the lens barrel 12 and the imaging device 13 therefore changes. The mechanism described above enables autofocusing (AF) (see JPA-2007-17791, for example).